Energy storage apparatus

ABSTRACT

An energy storage apparatus includes: an energy storage device; an outer covering; an end plate which is disposed on a side of the energy storage device and is fixed to the outer covering; and a binding member which is mounted on the end plate and applies a binding force to the energy storage device. The end plate includes a first region on which the binding member is mounted, a second region which is fixed to the outer covering, and a third region which differs from the first region and the second region and has higher rigidity than the first region and the second region.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese patent application No.2015-186037, filed on Sep. 18, 2015, which is incorporated by reference.

FIELD

The present invention relates to an energy storage apparatus providedwith an energy storage device and an outer covering.

BACKGROUND

Conventionally, as an energy storage apparatus provided with energystorage devices, there has been known the configuration where energystorage devices are sandwiched by plates (end plates) (see JP2010-272251 A, for example). In such an energy storage apparatus, thepair of plates sandwiches the energy storage devices by a binding forceapplied by bind bars (binding members) mounted on the pair of plates.

In the above-mentioned conventional configuration, the end plates areheld in a state where a binding force generated by the binding member isapplied to the energy storage devices and hence, there may be a casewhere deformation such as deflection occurs in the end plates.

SUMMARY

The following presents a simplified summary of the invention disclosedherein in order to provide a basic understanding of some aspects of theinvention. This summary is not an extensive overview of the invention.It is intended to neither identify key or critical elements of theinvention nor delineate the scope of the invention. Its sole purpose isto present some concepts of the invention in a simplified form as aprelude to the more detailed description that is presented later.

An object of the present invention to provide an energy storageapparatus which can suppress the deformation of end plates.

According to an aspect of the present invention, there is provided anenergy storage apparatus which includes: an energy storage device; anouter covering; an end plate which is disposed on a side of the energystorage device and is fixed to the outer covering; and a binding memberwhich is mounted on the end plate and applies a binding force to theenergy storage device, wherein the end plate includes a first region onwhich the binding member is mounted, a second region which is fixed tothe outer covering, and a third region which differs from the firstregion and the second region and has higher rigidity than the firstregion and the second region.

BRIEF DESCRIPTION OF DRAWINGS

The foregoing and other features of the present invention will becomeapparent from the following description and drawings of an illustrativeembodiment of the invention in which:

FIG. 1 is a perspective view showing an external appearance of an energystorage apparatus according to an embodiment.

FIG. 2 is an exploded perspective view showing constitutional elementsof the energy storage apparatus.

FIG. 3 is an exploded perspective view showing constitutional elementsof an energy storage unit.

FIG. 4 is a perspective view showing a configuration of the energystorage apparatus where spacers are removed from the energy storageunit.

FIG. 5 is an exploded perspective view showing constitutional elementsof a sandwiching member.

FIGS. 6A-6B is a view showing a detailed configuration of a metal endplate.

FIG. 7 is a perspective view showing a mode where the energy storageunit and an outer covering are fixed to each other.

FIG. 8 is a cross-sectional view showing a state where the energystorage unit is housed in the outer covering.

FIG. 9 is an exploded perspective view showing constitutional elementsof an energy storage apparatus according to a modification.

DESCRIPTION OF EMBODIMENTS

According to an aspect of the present invention, there is provided anenergy storage apparatus which includes: an energy storage device; anouter covering; an end plate which is disposed on a side of the energystorage device and is fixed to the outer covering; and a binding memberwhich is mounted on the end plate and applies a binding force to theenergy storage device, wherein the end plate includes a first region onwhich the binding member is mounted, a second region which is fixed tothe outer covering, and a third region which differs from the firstregion and the second region and has higher rigidity than the firstregion and the second region.

Since the binding member is mounted on the first region, the deformationof the first region is suppressed by the binding member. Since the outercovering is fixed to the second region, the deformation of the secondregion is suppressed by the outer covering. That is, both thedeformation of the first region and the second region are suppressed bythe other members which are connected to the end plate. The third regionwhich differs from the first region and the second region has higherrigidity than the first region and the second region and hence, thedeformation of the third region is suppressed by the rigidity of the endplate per se without relying on other members. Since all of thedeformation of the first region, the second region and the third regionare suppressed, the deformation of the end plate can be suppressed.

The third region may be formed of a plurality of plate members which aremade to overlap with each other.

With such a configuration, the third region is formed of the pluralityof plate members which are made to overlap with each other and hence,the rigidity of the third region can be increased with the simpleconfiguration.

A strip-like projecting portion may be formed on the third region.

With such a configuration, the strip-like projecting portion is formedon the third region and hence, the rigidity of the third region can beincreased while the increase of a material and a weight of the end plateare suppressed.

The projecting portion may be formed in an extending manner from thefirst region to the second region.

With such a configuration, the projecting portion is formed in anextending manner from the first region to the second region and hence,the rigidity of the third region can be further increased.

The outer covering may have a recessed portion which is recessed towardthe end plate, and the second region may be disposed at a positioncorresponding to the recessed portion and may be fixed to the recessedportion.

With such a configuration, the second region is disposed at a positioncorresponding to the recessed portion of the outer covering and hence,the second region is positioned more inner side of the outer coveringcompared to a case where the outer covering has no such recessedportion. Accordingly, in the case where the third region is positionedbetween the first region and the second region, a size of the thirdregion can be made small. As a result, the deformation which occurs onthe third region when a stress is applied thereto can be furthersuppressed.

According to another aspect of the present invention, there is providedan energy storage apparatus which includes: an energy storage device; anouter covering; an end plate which is disposed on a side of the energystorage device; and a binding member which is mounted on the end plateand applies a binding force to the energy storage device, wherein theend plate has a first region where the binding member is mounted and athird region which differs from the first region and has higher rigiditythan the first region.

Since the binding member is mounted on the first region, the deformationof the first region is suppressed by the binding member. That is, thedeformation of the first region is suppressed by other members connectedto the end plate. The third region which differs from the first regionhas higher rigidity than the first region and hence, the deformation ofthe third region is suppressed by the rigidity of the end plate per sewithout relying on other members. Both the deformation of the firstregion and the third region are suppressed and hence, the deformation ofthe end plate can be suppressed.

The energy storage apparatus of the present invention can suppress thedeformation of the end plate.

Hereinafter, an energy storage apparatus according to an embodiment ofthe present invention is described with reference to drawings. Theembodiment described hereinafter is one preferred specific example ofthe present invention. In the embodiment described hereinafter,numerical values, shapes, materials, constitutional elements, thearrangement positions and connection states of the constitutionalelements and the like are merely examples, and these are not intended tolimit the present invention. Further, out of the constitutional elementsin the embodiment described hereinafter, the constitutional elementswhich are not described in independent claims describing an uppermostconcept are described as arbitrary constitutional elements. In therespective drawings, the respective constitutional elements are notdescribed strictly accurately in size or the like.

Embodiment

First, a configuration of an energy storage apparatus 1 is described.

FIG. 1 is a perspective view showing an external appearance of theenergy storage apparatus 1 according to an embodiment of the presentinvention. FIG. 2 is an exploded perspective view showing constitutionalelements of the energy storage apparatus 1.

In these drawings, the Z axis direction is indicated as the verticaldirection, and the description is made hereinafter using the Z axisdirection as the vertical direction. However, there may be also a casewhere the Z axis direction is not the vertical direction depending on amode of use and hence, the Z axis direction is not limited to thevertical direction. The same goes for drawings which are referencedhereinafter.

The energy storage apparatus 1 is an apparatus which can chargeelectricity from the outside of the energy storage apparatus 1 thereinor can discharge electricity to the outside of the energy storageapparatus 1. For example, the energy storage apparatus 1 may be abattery module used for power storage application, power sourceapplication or the like. As shown in FIG. 1 and FIG. 2, the energystorage apparatus 1 includes: an outer covering 10 formed of a firstouter covering 11 and a second outer covering 12; and an energy storageunit 20, a holder 30, bus bars 41, 42, thermistors 50 and the like whichare housed in the outer covering 10.

The outer covering 10 is a container (module case) having a rectangularshape (box shape) which forms an outer covering of the energy storageapparatus 1. That is, the outer covering 10 is disposed outside theenergy storage unit 20, the holder 30, the bus bars 41, 42 and thethermistors 50 and allows the energy storage unit 20 and the like to bedisposed at predetermined positions in the outer covering 10 thusprotecting the energy storage unit 20 and the like from an impact or thelike. In this embodiment, for example, the outer covering 10 is made ofan insulating resin material such as polycarbonate (PC), polypropylene(PP), polyethylene (PE), a polyphenylene sulfide resin (PPS),polybutylene terephthalate (PBT) or an ABS resin. The outer covering 10prevents the energy storage unit 20 and the like from coming intocontact with a metal member or the like disposed outside the outercovering 10.

The energy storage apparatus 1 of this embodiment is preferably used asa vehicle-mounted energy storage apparatus. However, the energy storageapparatus 1 is not limited to such an energy storage apparatus. In thisembodiment, the outer covering 10 is formed to have the same size andthe same shape as an outer covering of a vehicle-mounted lead-acidbattery. That is, the energy storage apparatus 1 is configured to bereplaceable with the lead-acid battery. The energy storage apparatus 1outputs, for starting an engine of a vehicle, a voltage of approximately12 V in a state where the energy storage unit 20 is fully charged.

An output from the energy storage apparatus 1 may be used for, besidesstarting an engine, supplying electricity to accessories or assistingdriving of a vehicle. The energy storage apparatus 1 may output avoltage higher than 12 V (approximately 48 V, for example) in a statewhere the energy storage unit 20 is fully charged.

The outer covering 10 includes: the first outer covering 11 forming alid body of the outer covering 10; and the second outer covering 12forming a body of the outer covering 10. The first outer covering 11 isa cover member having a flat rectangular shape which closes an openingof the second outer covering 12. A positive electrode external terminal13 and a negative electrode external terminal 14 are mounted on thefirst outer covering 11. The energy storage apparatus 1 chargeselectricity from the outside therein or discharges electricity to theoutside through the positive electrode external terminal 13 and thenegative electrode external terminal 14. The second outer covering 12 isa bottomed rectangular cylindrical housing having the opening The secondouter covering 12 houses the energy storage unit 20, the holder 30, thebus bars 41, 42, the thermistors 50 and the like.

The first outer covering 11 and the second outer covering 12 may be madeof the same material, or may be made of different materials.

Electric equipment such as a printed circuit board and a relay isdisposed in the first outer covering 11. However, the illustration ofsuch electric equipment is omitted. The first outer covering 11 isconfigured to be divided into two members in the vertical direction (Zaxis direction), and such electric equipment is disposed between suchtwo members. With such a configuration, the electric equipment isprotected from an impact or the like, and is also prevented from cominginto contact with a metal member or the like disposed outside the firstouter covering 11.

On the printed circuit board, a control circuit is mounted. The controlcircuit is connected to the energy storage device 100 in the energystorage unit 20 described later through wires, for example, andacquires, monitors and controls various kinds of information such as acharging state and a discharging state, a voltage value, a currentvalue, and a temperature of the energy storage device 100. Further, thecontrol circuit controls ON and OFF of relays and performs communicationwith other apparatuses. A temperature of the energy storage device 100means a temperature obtained by using a thermistor 50. That is, thecontrol circuit is connected with the thermistor 50 which is disposed incontact with the energy storage device 100 through a wire (lead line),and a temperature of the energy storage device 100 can be acquired byconverting information (resistance value) transmitted from thethermistor 50 into a temperature.

The energy storage unit 20 includes a plurality of energy storagedevices 100 (twelve energy storage devices 100 in this embodiment) and aplurality of bus bars 200, and is electrically connected to the positiveelectrode external terminal 13 and the negative electrode externalterminal 14 formed on the first outer covering 11. That is, a positiveelectrode terminal of any one of the plurality of energy storage devices100 is electrically connected to the positive electrode externalterminal 13 through the bus bar 200. A negative electrode terminal ofany one of the plurality of energy storage devices 100 is electricallyconnected to the negative electrode external terminal 14 through the busbar 200.

The energy storage unit 20 is disposed in the second outer covering 12such that the plurality of energy storage devices 100 are arranged in arow in the X axis direction in a state where each energy storage device100 is mounted vertically (in a state where a positive electrodeterminal and a negative electrode terminal are directed upward). Theenergy storage unit 20 is housed in the outer covering 10 while beingcovered by the first outer covering 11 from above. The detaileddescription of the configuration of the energy storage unit 20 and thedetailed description of the configuration where the energy storage unit20 and the outer covering 10 are fixed to each other are made later.

The holder 30 is an electronic component tray. The holder 30 is providedfor holding electronic components such as the bus bars 41, 42, andrelays, wires (not shown in the drawing). The holder 30 also providesinsulation between the bus bars 41, 42 and the like and other members.The holder 30 further regulates the positions of the bus bars 41, 42 andthe like. Particularly, the holder 30 positions the bus bars 41, 42 withrespect to the bus bars 200 in the energy storage unit 20, the positiveelectrode external terminal 13, and the negative electrode externalterminal 14.

To be more specific, the holder 30 is placed on an upper portion (a plusside in the Z axis direction) of the energy storage unit 20, and ispositioned with respect to the energy storage unit 20. The bus bars 41,42 are placed on the holder 30 and are positioned with respect to theholder 30. The first outer covering 11 is disposed on the holder 30.With such a configuration, the bus bars 41, 42 are positioned withrespect to the bus bars 200 in the energy storage unit 20, and thepositive electrode external terminal 13 and the negative electrodeexternal terminal 14 mounted on the first outer covering 11.

The holder 30 also has a function of holding the thermistor 50. That is,opening portions are formed in the holder 30. By inserting thethermistors 50 into the opening portions and by rotating the thermistors50, the thermistors 50 are positioned with respect to the energy storagedevice 100, and is fixed to the energy storage device 100 in a pressedstate.

Although the holder 30 is made of an insulating resin material such asPC, PP, PE, PPS, PBT or an ABS resin, the holder 30 may be made of anymaterial as long as a material has an insulating property.

The bus bars 41, 42 electrically connect the bus bars 200 in the energystorage unit 20 and the positive electrode external terminal 13 and thenegative electrode external terminal 14 mounted on the first outercovering 11 to each other. That is, the bus bar 41 is a conductivemember which electrically connects the bus bars 200 disposed on one endin the energy storage unit 20 and the positive electrode externalterminal 13 to each other, and the bus bar 42 is a conductive memberwhich electrically connects the bus bars 200 disposed on the other endin the energy storage unit 20 and the negative electrode externalterminal 14 to each other.

The bus bars 41, 42 are made of copper, for example, as conductivemembers. However, a material for forming the bus bars 41, 42 is notparticularly limited. The bus bars 41, 42 may be made of the samematerial, or may be made of different materials.

The thermistor 50 is a temperature sensor which is mounted on the energystorage device 100. That is, the thermistor 50 is mounted in a statewhere the thermistor 50 is pressed to the lid portion of the energystorage device 100. The thermistor 50 measures a temperature of theenergy storage device 100. In this embodiment, two thermistors 50 aredisposed for two energy storage devices 100.

To be more specific, the thermistors 50 are mounted on the holder 30after the holder 30 is mounted on the energy storage devices 100.Accordingly, the thermistors 50 are positioned with respect to theenergy storage devices 100, and are disposed in a state where thethermistors 50 are pressed to the energy storage devices 100. Theprinciple by which the thermistor 50 measures a temperature of theenergy storage device 100 is substantially equal to the principle behinda conventional thermistor and hence, the detailed description of theprinciple is omitted.

Next, the configuration of the energy storage unit 20 is described indetail.

FIG. 3 is an exploded perspective view showing constitutional elementsof the energy storage unit 20.

The energy storage unit 20 includes: the plurality of energy storagedevices 100; the plurality of bus bars 200; a plurality of spacers 300(a plurality of spacers 310 and a pair of spacers 320); a pair ofsandwiching members 400; a plurality of binding members 500; a bus barframe 600; and a heat insulating plate 700.

The energy storage device 100 is a secondary battery (battery) which cancharge or discharge electricity. To be more specific, the energy storagedevice 100 is a nonaqueous electrolyte secondary battery such as alithium ion secondary battery. The energy storage device 100 has a flatrectangular shape, and is disposed adjacently to the spacer 310. Thatis, the plurality of energy storage devices 100 and the plurality ofrespective spacers 310 are arranged in a row in the X axis directionsuch that the energy storage device 100 and the spacer 310 arealternately arranged. In this embodiment, twelve energy storage devices100 and eleven spacers 310 are arranged such that the energy storagedevice 100 and the spacer 310 are alternately arranged. The energystorage device 100 is not limited to a nonaqueous electrolyte secondarybattery, and may be a secondary battery other than a nonaqueouselectrolyte secondary battery, or may be a capacitor.

As shown in FIG. 3, the energy storage device 100 includes a container110, the positive electrode terminal 120 and the negative electrodeterminal 130. An electrode assembly (power generating element), currentcollectors (a positive electrode current collector and a negativeelectrode current collector) and the like are disposed in the container110, and a liquid such as an electrolyte solution (nonaqueouselectrolyte) is sealed in the container 110. However, the detaileddescription of such a configuration is omitted.

The container 110 is formed of: a bottomed container body made of metaland having a rectangular cylindrical shape; and a metal-made lid portionwhich closes an opening of the container body. The container 110 isconfigured such that the inside of the container 110 is hermeticallysealed by joining the lid portion and the container body to each otherby welding or the like after the electrode assembly and the like arehoused in the container 110. The container 110 is a rectangularparallelepiped container having a lid portion disposed on a plus side inthe Z axis direction, long side surfaces disposed on side surfaces ofthe container on both sides in the X axis direction, short side surfacesdisposed on side surfaces of the container on both sides in the Y axisdirection, and a bottom surface disposed on a minus side in the Z axisdirection. Although a material for forming the container 110 is notparticularly limited, it is preferable that the container 110 be made ofweldable metal such as stainless steel, aluminum or an aluminum alloy.

The positive electrode terminal 120 is an electrode terminalelectrically connected to a positive electrode of an electrode assemblythrough a positive electrode current collector. The negative electrodeterminal 130 is an electrode terminal electrically connected to anegative electrode of an electrode assembly through a negative electrodecurrent collector. Both the positive electrode terminal 120 and thenegative electrode terminal 130 are mounted on the lid portion of thecontainer 110. That is, the positive electrode terminal 120 and thenegative electrode terminal 130 are metal-made electrode terminalsthrough which electricity stored in the electrode assembly is dischargedto a space outside the energy storage device 100, and through whichelectricity is introduced into a space inside the energy storage device100 for storing the electricity in the electrode assembly. In thisembodiment, the energy storage devices 100 are disposed in a state wherethe positive electrode terminals 120 and the negative electrodeterminals 130 are directed upward.

The bus bars 200 are electrically connected to the plurality ofrespective energy storage devices 100 housed in the energy storage unit20. That is, the bus bars 200 are conductive members electricallyconnected to the respective electrode terminals which the plurality ofenergy storage devices 100 include in a state where either one ofpositive and negative electrode terminals of one energy storage device100 is electrically connected to the corresponding terminal of anotherenergy storage device 100 disposed adjacently to one energy storagedevice. The bus bars 200 are disposed on surfaces of the respectiveelectrode terminals which the plurality of energy storage devices 100include, and are connected (joined) to the electrode terminals.

In this embodiment, five bus bars 200 are disposed. Twelve energystorage devices 100 are configured such that four sets of energy storagedevices 100 each of which is formed by connecting three energy storagedevices 100 in parallel to each other are connected in series by fivebus bars 200. The bus bars 200 disposed at end portions of the energystorage unit 20 are connected to the above-mentioned bus bars 41, 42respectively. With such a configuration, the energy storage devices 100are electrically connected to the positive electrode external terminal13 and the negative electrode external terminal 14.

The bus bars 200 are made of aluminum, for example, as conductivemembers. However, a material for forming the bus bar 200 is notparticularly limited. All bus bars 200 may be made of the same material,or some of the bus bars 200 may be made of different materials.

The spacers 300 are formed of the plurality of spacers 310 and the pairof spacers 320, and are made of an insulating resin such as PC, PP, PE,PPS, PBT or an ABS resin. The spacers 310 and 320 may be made of anymaterial as long as the spacers have an insulating property. All ofspacers 310 and 320 may be made of the same material, or some of thespacers 310 and 320 may be made of different materials respectively.

The spacer 310 is a plate-like member which is disposed on a side of theenergy storage device 100 (on the plus side or the minus side in the Xaxis direction) so as to provide insulation between the energy storagedevice 100 and other members. That is, the spacer 310 is arrangedbetween two energy storage devices 100 disposed adjacently to each otherso as to provide insulation between two energy storage devices 100. Inthis embodiment, twelve energy storage devices 100 and eleven spacers310 are arranged in a row such that the spacer 310 is disposed betweentwo energy storage devices 100 disposed adjacently to each other.

The spacer 310 is formed such that the spacer 310 covers anapproximately half of a front surface side or a back surface side of theenergy storage device 100 (an approximately half of the front surfaceside or the back surface side when the energy storage device 100 isdivided in two in the X axis direction). That is, a recessed portion isformed on both surfaces (both surfaces in the X axis direction) of thespacer 310 on the front surface side and the back surface siderespectively, and an approximately half of the energy storage device 100is inserted into each recessed portion. With such a configuration, thespacers 310 disposed on sides of the energy storage device 100 cover themost part of the energy storage device 100. Accordingly, an insulatingproperty between the energy storage devices 100 and other conductivemembers can be enhanced by the spacers 310. The spacer 310 is formedsuch that the spacer 310 does not cover a portion of the energy storagedevice 100 at which the thermistor 50 is positioned so as to allow thethermistor 50 to be brought into contact with the energy storage device100.

The spacer 320 is a plate-like member which is disposed between thesandwiching member 400 described later and the outer covering 10, andprovides insulation between the sandwiching member 400 and the outercovering 10. The spacer 320 also has a function as a buffer member whichprotects the energy storage unit 20 when an impact is applied to theouter covering 10 from the outside. The pair of spacers 320 is disposedbetween the pair of sandwiching members 400 and the outer covering 10respectively such that the pair of spacers 320 sandwiches the pair ofsandwiching members 400 from both sides. The pair of spacers 320insulates the energy storage devices 100 and the like disposed in theenergy storage unit 20 and also protects the energy storage devices 100and the like from an impact from the outside.

The sandwiching members 400 and the binding members 500 are memberswhich press the energy storage devices 100 from the outside in thestacking direction of the electrode assembly of the energy storagedevice 100. That is, the sandwiching member 400 and the binding member500 sandwich the plurality of energy storage devices 100 from both sidesin the stacking direction thus pressing the plurality of respectiveenergy storage devices 100 from both sides. In this embodiment, thestacking direction of the electrode assembly of the energy storagedevices 100 means the direction that positive electrodes, negativeelectrodes and separators of the electrode assembly are stacked, and isequal to the direction (X axis direction) that the plurality of energystorage devices 100 are arranged in a row. That is, the plurality ofenergy storage devices 100 are arranged in a row in the stackingdirection.

To be more specific, the sandwiching members 400 are flat plate-likemembers (end plates) disposed on both sides of a unit formed of theplurality of energy storage devices 100 in the X axis direction. Thesandwiching members 400 hold the plurality of energy storage devices 100and the plurality of spacers 310 by sandwiching the unit formed of theplurality of energy storage devices 100 and the plurality of spacers 310from both sides in the arrangement direction (X axis direction) of theplurality of energy storage devices 100 and the plurality of spacers310. The detailed configuration of the sandwiching member 400 isdescribed later.

The binding member 500 is an elongated flat-plate-like member (bindingbar) which has both ends thereof mounted on the sandwiching members 400,and binds the plurality of energy storage devices 100 to each other.That is, the binding member 500 is disposed so as to straddle over theplurality of energy storage devices 100 and the plurality of spacers 310thus applying a binding force in the arrangement direction (X axisdirection) of the plurality of energy storage devices 100 and pluralityof spacers 310 to the plurality of energy storage devices 100 andplurality of spacers 310.

In this embodiment, two binding members 500 are disposed on both sides(both sides in the Y axis direction) of the unit formed of the pluralityof energy storage devices 100, and two binding members 500 bind theplurality of energy storage devices 100 to each other by sandwiching theplurality of energy storage devices 100 from both sides. In the samemanner as the sandwiching members 400, the binding members 500 arepreferably made of metal such as stainless steel or aluminum. However,the binding members 500 may be made of a material other than metal.

The bus bar frame 600 is a member which can provide insulation betweenthe bus bars 200 and other members, and can regulate the positions ofthe bus bars 200. Particularly, the bus bar frame 600 performs thepositioning of the bus bars 200 with respect to the plurality of energystorage devices 100 disposed in the energy storage unit 20.

To be more specific, the bus bar frame 600 is disposed on an upper sideof the plurality of energy storage devices 100 (a plus side in the Zaxis direction), and is positioned with respect to the plurality ofenergy storage devices 100. Although the bus bar frame 600 is made of aninsulating resin material such as PC, PP, PE, PPS, PBT or an ABS resin,the bus bar frame 600 may be made of any material as long as thematerial has an insulating property.

Two thermistor-use opening portions being through holes through whichtwo thermistors 50 are respectively inserted are formed on the bus barframe 600. Two thermistors 50 are respectively inserted through twothermistor-use opening portions, and are brought into contact with thelid portions of the containers 110 of the energy storage devices 100.

A heat insulating plate 700 is a plate-like member having a heatinsulating property. The heat insulating plate 700 is disposed in a flowpassage for a gas discharged from safety valves of the energy storagedevices 100. The heat insulating plate 700 is disposed above the bus barframe 600 such that the heat insulating plate 700 is positioned abovethe safety valves of the energy storage devices 100. When an abnormalstate occurs where a gas is discharged from the safety valve of theenergy storage device 100, the heat insulating plate 700 protectselectric equipment such as a printed circuit board disposed above theenergy storage unit 20 from heat of the gas. In this embodiment, theheat insulating plate 700 is made of a metal material having low thermalconductivity such as stainless steel. However, a material for formingthe heat insulating plate 700 is not limited to such a metal material,and the heat insulating plate 700 may be made of a resin such as PPS orPBT which is reinforced by glass fibers or ceramics, as long as thematerial has high heat resistance and low thermal conductivity.

Next, the configuration of the sandwiching member 400 is described indetail. Two sandwiching members 400 have the same configuration.Accordingly, the description is made only on one sandwiching member 400(the sandwiching member 400 disposed on a plus side in the X axisdirection) hereinafter, and the description of the other sandwichingmember 400 is omitted.

FIG. 4 is a perspective view showing a configuration where the spacers300 are removed from the energy storage unit 20 according to theembodiment of the present invention.

As shown in FIG. 4, a pair of binding members 500 and the heatinsulating plate 700 are mounted on the sandwiching members 400. To bemore specific, both end portions of each sandwiching member 400 in the Yaxis direction are respectively mounted on end portions of the bindingmembers 500 in a longitudinal direction (in this embodiment, endportions in the X axis direction) by screws 501, and a center portion ofeach sandwiching members 400 in the Y axis direction is mounted on eachend portion of the heat insulating plate 700 in a longitudinal direction(in this embodiment, each end portion in the X axis direction) by screws711.

The sandwiching member 400 is configured such that a plate-likeresin-made member which is disposed on an energy storage device 100 side(a minus side in the X axis direction) and a plate-like metal-mademember which is disposed on a side opposite to the energy storage device100 (a plus side in the X axis direction) are made to overlap with eachother. This configuration is described with reference to FIG. 5.

FIG. 5 is an exploded perspective view showing constitutional elementsof the sandwiching member 400.

As shown in FIG. 5, the sandwiching member 400 includes a resin endplate 410 and a metal end plate 420 which are disposed adjacently to theenergy storage device 100 in this order.

The resin end plate 410 is disposed between the energy storage device100 disposed at an end portion among the plurality of energy storagedevices 100 in the energy storage unit 20 and the metal end plate 420 soas to provide insulation between the energy storage device 100 and themetal end plate 420. Although the resin end plate 410 is made of aninsulating resin such as PC, PP, PE, PPS, PBT or an ABS resin, the resinend plate 410 may be made of any material as long as the material has aninsulating property.

To be more specific, the resin end plate 410 is formed such that theresin end plate 410 covers an approximately half on a front surface side(a plus side in the X axis direction) of the energy storage device 100disposed on an end portion on a plus side in the X axis direction. Thatis, a recessed portion is formed on a back surface side (a minus side inthe X axis direction) of the resin end plate 410, and an approximatelyhalf of the above-mentioned energy storage device 100 is inserted intothe recessed portion. With such a configuration, the spacer 310 and theresin end plate 410 which sandwich the above-mentioned energy storagedevice 100 therebetween cover the most part of the energy storage device100. Accordingly, an insulating property between the energy storagedevice 100 and other conductive members can be enhanced by the spacer310 and the resin end plate 410.

The resin end plate 410 is formed such that the resin end plate 410covers a back surface side (a minus side in the X axis direction) of themetal end plate 420. That is, a recessed portion is formed on a frontsurface side of the resin end plate 410, and the back surface side ofthe metal end plate 420 is inserted into the recessed portion. With sucha configuration, an insulating property between the energy storagedevice 100 and the metal end plate 420 can be enhanced by the resin endplate 410.

In this embodiment, projecting portions 411 which project toward themetal end plate 420 are formed on the resin end plate 410. Theprojecting portions 411 are disposed in recessed portions which areformed on the back surface of the metal end plate 420 due to bulging ofportions of the metal end plate 420 toward the outside of the outercovering 10, and end portions of the projecting portions in a projectingdirection are brought into contact with bottom surfaces of the recessedportions. With such a configuration, even when a portion of the metalend plate 420 is formed in a bulging manner, a binding force generatedby the binding members 500 can be efficiently applied to the energystorage devices 100.

The projecting portion 411 is formed of a grid-like continuous wall, forexample. The shape of the projecting portion 411 is not limited to sucha shape, and the projecting portion 411 may have a columnar shape, forexample. The projecting portion 411 may be a portion of the resin endplate 410 which has a large wall thickness. Further, the resin end plate410 may not have the projecting portion 411, but have a flat plateshape.

Two protruding portions 412 which project upward are formed on an upperend portion (an end portion on a plus side in the Z axis direction) ofthe resin end plate 410. The resin end plate 410 positions the bus barframe 600 with respect to the plurality of energy storage devices 100 bytwo protruding portions 412, for example. Further, two protrudingportions 413 which project outward are formed on both end portions ofthe resin end plate 410 in the Y axis direction respectively. The resinend plate 410 positions the binding members 500 with respect to theplurality of energy storage devices 100 and the sandwiching member 400by two protruding portions 413 disposed on both end portions of theresin end plate 410 in the Y axis direction respectively, for example.The resin end plate 410 may not be provided with the protruding portions412, 413.

The metal end plate 420 is disposed on a front surface side of the resinend plate 410 having the above-mentioned configuration.

The metal end plates 420 are flat plate-like members which sandwich andhold the plurality of energy storage devices 100, the plurality ofspacers 310, and the resin end plates 410 from both sides in thearrangement direction of these components (X axis direction). The metalend plate 420 has binding portions 421 on which the binding members 500are respectively mounted, a fixing portion 422 which is fixed to theouter covering 10, a high rigidity portion 423, and a heat insulatingplate mounting portion 424 on which the heat insulating plate 700 ismounted.

The metal end plate 420 includes a plurality of members which are madeto overlap with each other. Such a configuration is described also withreference to FIGS. 6A-6B.

FIGS. 6A-6B is a view showing the detailed configuration of the metalend plate 420. FIG. 6A is a perspective view of the metal end plate 420,and FIG. 6B is a cross-sectional view of the metal end plate 420 takenalong a line VI-VI in FIG. 6A which is a perspective view.

As shown in FIG. 5 and FIGS. 6A-6B, the metal end plate 420 includes aplate member 425 and a plate member 426 which are disposed in this orderfrom an energy storage device 100 side. The binding portion 421 and theheat insulating plate mounting portion 424 are formed of the platemember 425. The high rigidity portion 423 is formed of the plate member425 and the plate member 426. The fixing portion 422 is formed of theplate member 426.

Hereinafter, the detailed configuration of the metal end plate 420 isdescribed.

First, the plate members 425, 426 which form the metal end plate 420 aredescribed in detail.

The plate member 425 is a metal-made plate-like member having anapproximately rectangular shape which is disposed in the recessedportion formed on a front surface side of the resin end plate 410 andhas an outer profile slightly smaller than a profile of the recessedportion. The plate member 425 forms the binding portions 421 and theheat insulating plate mounting portion 424. The plate member 425 alsoforms the high rigidity portion 423 together with the plate member 426.

The plate member 426 is a metal-made plate-like member having a stripshape which is disposed on the front surface side of the plate member425 in an overlapping manner. With such an outer profile, the platemember 426 has a smaller width (a size in the Z axis direction) than theplate member 425. The plate member 426 is disposed at a positiondifferent from a position where the binding portions 421 and the heatinsulating plate mounting portion 424 are disposed, and is integrallyformed (integrated) with the plate member 425 by spot welding or thelike. That is, the plate member 426 and the plate member 425 are made tooverlap with each other in a state where the plate member 425 and theplate member 426 are difficult to be separated from each other. To bemore specific, the plate member 426 is disposed such that an upperportion (a portion on a plus side in the Z axis direction, anoverlapping portion) of the plate member 426 is made to overlap with theplate member 425. That is, the upper portion of the plate member 426 isformed integrally with the plate member 425 thus forming the highrigidity portion 423. A lower portion (a portion on a minus side in theZ axis direction, a flange portion) of the plate member 426 is benttoward the outside of the outer covering 10, and forms the fixingportion 422.

From a viewpoint of strength, easiness in forming and the like, forexample, the plate members 425, 426 are weldable metal-made membersformed using a steel plate for general structure, a plated steel plate,a high tensile steel plate obtained by enhancing strength of the steelplate or the plated steel plate, stainless steel, aluminum or analuminum alloy. The material for forming the plate members 425, 426 isnot limited to such materials, and the plate members 425, 426 may bemade of metal other than metals described above, a resin having highstrength or the like, for example.

Next, the detailed configurations of respective portions of the metalend plate 420 (binding portions 421, fixing portion 422, high rigidityportion 423 and heat insulating plate mounting portion 424) aredescribed with reference to FIG. 4 to FIGS. 6A-6B.

As shown in these drawings, the binding portions 421 are portions of thesandwiching member 400 on which the binding members 500 are mounted, andare disposed in a first region. In this embodiment, the binding portion421 is formed on both end portions of the metal end plate 420 in the Yaxis direction respectively. In each binding portion 421, through holes421 a into which screws 501 for mounting the binding member 500 on themetal end plate 420 are inserted are formed. It is sufficient that thethrough holes 421 a are formed so as to correspond to through holes (notshown in the drawing) formed in the binding member 500 into which thescrews 501 are inserted. Although the number of through holes 421 a isnot particularly limited, in this embodiment, two through holes 421 aare formed in each binding portion 421.

The binding portions 421 are formed in a bulging manner toward theoutside of the outer covering 10 by press working or the like. Thebinding portions 421 are ribs projecting toward the outside of the outercovering 10. Two through holes 421 a are formed in a distal end of therib.

The fixing portion 422 is a portion of the sandwiching member 400 to befixed to the outer covering 10, and is disposed in a second region. Inthis embodiment, the fixing portion 422 is disposed slightly inside(above) the lower end portion 420 a (an end portion on a minus side inthe Z axis direction) of the metal end plate 420. In the fixing portion422, through holes 422 a into which fastening jigs for fixing the metalend plate 420 to the outer covering 10 are inserted are formed. It issufficient that the through holes 422 a are formed so as to correspondto through holes (not shown in the drawing) formed in the outer covering10 into which the fastening jigs are inserted. Although the number ofthrough holes 422 a is not particularly limited, in this embodiment, twothrough holes 422 a are formed in the fixing portion 422. Theconfiguration where the fixing portion 422 and the outer covering 10 arefixed to each other is described later along with the configurationwhere the energy storage unit 20 and the outer covering 10 are fixed toeach other.

The fixing portion 422 projects toward the outside of the outer covering10 from the other portion of the metal end plate 420. To be morespecific, the fixing portion 422 projects toward the outside (a plusside in the X axis direction) of the outer covering 10 along thearrangement direction (X axis direction) of the energy storage devices100. With such a configuration, the outer covering 10 is fixed to thefixing portion 422 in a state where the outer covering 10 houses theenergy storage unit 20 therein and, at the same time, the outer covering10 can apply a binding force to the energy storage devices 100 in thearrangement direction of the energy storage devices 100.

The high rigidity portion 423 is a portion which is different from thebinding portions 421 and the fixing portion 422 and has higher rigiditythan the binding portions 421 and the fixing portion 422. The highrigidity portion 423 is disposed in a third region. The rigidity of thebinding portions 421, the fixing portion 422 and the high rigidityportion 423 can be evaluated, for example, by forming a shape of themetal end plate 420 as a 3D model using a Computer Aided Design (CAD) orby reading a shape of the metal end plate 420 from the actual metal endplate 420 by 3D scanning and, thereafter, by performing a Computer AidedEngineering (CAE) analysis or the like.

In this embodiment, the high rigidity portion 423 is disposed in anintermediate region between the binding portions 421 and the fixingportion 422. To be more specific, the high rigidity portion 423 isdisposed in a substantially whole area between the binding portions 421and the fixing portion 422 as well as between the heat insulating platemounting portion 424 and the fixing portion 422. The high rigidityportion 423 is provided over an entire width (entire width in the Y axisdirection) of the metal end plate 420 between the binding portions 421and the fixing portion 422.

An arrangement position and a size of the high rigidity portion 423 arenot particularly limited, and the high rigidity portion 423 may not bedisposed in the above-mentioned intermediate region, and may be disposedin a region outside a region where the binding portions 421 and thefixing portion 422 are embraced. The high rigidity portion 423 may notbe always formed over the entire width of the metal end plate 420, andmay be formed only over a partial width of the metal end plate 420.

From a viewpoint of suppressing the deformation of the sandwichingmember 400, it is preferable that the high rigidity portion 423 bedisposed in the above-mentioned intermediate region. Further, it ispreferable that the high rigidity portion 423 extend over the bindingportions 421 and the fixing portion 422. From the same viewpoint, it ispreferable that the high rigidity portion 423 be formed over the entirewidth of the sandwiching member 400. It is preferable that the highrigidity portion 423 be formed over the entire width of the energystorage device 100 or the entire width of the electrode assembly (notshown in the drawing) in the energy storage device 100 when thesandwiching member 400 and the energy storage device 100 are viewed inthe arrangement direction of the sandwiching members 400 and the energystorage devices 100.

In this embodiment, the high rigidity portion 423 is formed of aplurality of plate members (in this embodiment, two plate members 425,426) which are made to overlap with each other. To be more specific, thehigh rigidity portion 423 is formed of the plate member 425 and theplate member 426 which are formed into an integral body by spot weldingor the like. Accordingly, the high rigidity portion 423 has higherrigidity than the binding portions 421 and the heat insulating platemounting portion 424 which are respectively formed of only the platemember 425. In the same manner, the high rigidity portion 423 has higherrigidity than the fixing portion 422 which is formed of only the platemember 426.

A strip-like projecting portions 423 a are formed on the high rigidityportion 423. In this embodiment, two projecting portions 423 a areformed on the high rigidity portion 423 by forming portions of the platemember 426 in a projecting shape toward the outside of the outercovering 10 by press working.

The projecting portions 423 a are formed in an extending manner from thebinding portions 421 to the fixing portion 422 respectively. To be morespecific, the projecting portions 423 a are formed in an extendingmanner from the binding portions 421 and the heat insulating platemounting portion 424 to the fixing portion 422. For example, eachprojecting portion 423 a extends over the entire width of the highrigidity portion 423 along the Z axis direction, and in this embodiment,each projecting portion 423 a extends over the entire width of the platemember 425.

The number of projecting portions 423 a is not particularly limited, andmay be one or three or more. Also the projecting direction and theextending direction of the projecting portion 423 a are not particularlylimited. The projecting portion 423 a may be formed in a projectingmanner toward the outside of the outer covering 10, or may be formed inan extending manner in a direction other than the Z axis direction.

The heat insulating plate mounting portion 424 is a portion on which thebent portion formed on the end portion of the heat insulating plate 700in the X axis direction is mounted. Two through holes 424 a throughwhich screws 701 for fixing the bent portion to the metal end plate 420are inserted are formed in the heat insulating plate mounting portion424. That is, the heat insulating plate 700 is disposed so as tostraddle over the plurality of energy storage devices 100 in the energystorage unit 20, and both ends of the heat insulating plate 700 in thearrangement direction of the plurality of energy storage devices 100 arefixed to the sandwiching members 400. With such a configuration, when anabnormal state occurs, the heat insulating plate mounting portion 424can protect electric equipment such as a printed circuit board disposedabove the energy storage unit 20 from heat of a gas. At the same time,the heat insulating plate mounting portion 424 can apply a binding forceto the energy storage devices 100 in the arrangement direction of theenergy storage devices 100.

In this embodiment, the heat insulating plate mounting portion 424 isdisposed between two binding portions 421. The heat insulating platemounting portion 424 is formed in a bulging manner toward the outside ofthe outer covering 10 by press working or the like. The heat insulatingplate mounting portion 424 is a rib which projects toward the outside ofthe outer covering 10. Two through holes 424 a are formed in a distalend of the rib.

Next, a configuration where the sandwiching members 400 and the outercovering 10 are fixed to each other (that is, a configuration where theenergy storage unit 20 and the outer covering 10 are fixed to eachother) is described in detail.

FIG. 7 is a perspective view showing a mode where the energy storageunit 20 and the outer covering 10 (second outer covering 12) are fixedto each other. FIG. 7 shows the configuration of the energy storage unit20 although the illustration of the spacers 320 is omitted.

By fixing the sandwiching members 400 and the outer covering 10 (in thisembodiment, second outer covering 12) to each other, the energy storageunit 20 is fixed to the outer covering 10 in a state where the energystorage unit 20 is housed in the outer covering 10.

The outer covering 10 (second outer covering 12) has mounting portions12 a which are provided for the fastening jigs 21. The mounting portions12 a are formed of recessed portions each of which is recessed towardthe sandwiching member 400. The fixing portions 422 of the sandwichingmembers 400 are fixed to the mounting portions 12 a by the fasteningjigs 21. With such a configuration, the energy storage unit 20 is fixedto the second outer covering 12 in a state where the energy storage unit20 is housed in the second outer covering 12.

A through hole (not shown in the drawing) into which the fastening jig21 is inserted is formed in each mounting portion 12 a. The mountingportion 12 a forms a fastening portion where the outer covering 10 andthe sandwiching member 400 are fastened to each other.

The fastening jigs 21 are, for example, bolts which fix the sandwichingmember 400 to the outer covering 10 (in this embodiment, the secondouter covering 12). The mounting portions 12 a and the fixing portions422 are fastened to each other by inserting the fastening jigs 21 intothe through holes formed in the mounting portions 12 a and the throughholes 422 a formed in the fixing portions 422. The fastening jig 21 isnot limited to a bolt. For example, the fixing portion 422 may be formedof a male screw, and the fastening jig 21 may be formed of a nut.

Due to such fixing (fastening) by the fastening jigs 21, the energystorage unit 20 is fixed to the outer covering 10. As shown in FIG. 7,the energy storage unit 20 is fixed to the outer covering 10 also by anadhesive element 22 disposed between the energy storage devices 100 andthe outer covering 10. The adhesive element 22 fixes the energy storagedevices 100 in the energy storage unit 20 to the outer covering 10 at aposition different from positions where the fastening jigs 21 fix theenergy storage devices 100 to the outer covering 10. The adhesiveelement 22 is, for example, a double-coated adhesive tape. The adhesiveelement 22 is not limited to such a double-coated adhesive tape, and maybe an adhesive agent. Alternatively, the adhesive element 22 may be anadhesive element having a hook and loop fastener which allows theadhesion in a detachable manner and is referred to as Magic Tape(registered trademark) or Velcro tape (registered trademark).

The configuration of the energy storage unit 20 housed in the outercovering 10 as described above is described in detail hereinafter.

FIG. 8 is a cross-sectional view showing a state where the energystorage unit 20 is housed in the outer covering 10 (second outercovering 12). To be more specific, FIG. 8 is a cross-sectional viewtaken along a line VIII-VIII in the perspective view of FIG. 7 in astate where the energy storage unit 20 is housed in the outer covering10. In these drawings, among constitutional elements which form theenergy storage apparatus 1, the second outer covering 12 and the energystorage unit 20 are described and the illustration of otherconstitutional elements is omitted.

As shown in these drawings, the fixing portions 422 (second regions) aredisposed at positions corresponding to the mounting portions 12 a(recessed portions of the outer covering 10) and are fixed to themounting portions 12 a. The fixing portions 422 are disposed at aposition inside the outer covering 10 by an amount corresponding to adepth of the mounting portion 12 a (a depth of the recessed portion)compared to a case where the mounting portions 12 a are assumed to beformed without indentation. With such a configuration, a head portion 21a (an end portion on the outer side of the outer covering 10) of thefastening jig 21 is disposed in the mounting portion 12 a and hence, itis possible to suppress the projection of the fastening jigs 21 to theoutside of the outer covering 10.

As described above, the fixing portion 422 is disposed slightly insidethe lower end portion 420 a (see FIGS. 6A-6B) of the metal end plate420. Accordingly, an end edge (the end edge on the minus side in the Zaxis direction) of the lower end portion 420 a is disposed at a positionrelatively close to an inner wall of the outer covering 10. Accordingly,as shown in FIG. 8, the plurality of energy storage devices 100 can bedisposed at a position relatively close to the inner wall. With such aconfiguration, while a large arrangement space for arranging the energystorage devices 100 is ensured in the outer covering 10, it is possibleto suppress the projection of the fastening jigs 21 to the outside ofthe outer covering 10.

As has been described above, according to the energy storage apparatus 1of this embodiment, since the binding member 500 is mounted in the firstregion (in this embodiment, the binding portion 421), the deformation ofthe first region is suppressed by the binding member 500. Since thesecond region (in this embodiment, the fixing portion 422) is fixed tothe outer covering 10, the deformation of the second region issuppressed by the outer covering 10. That is, both the deformation ofthe first region and the second region are suppressed by the othermembers which are connected to the end plate (in this embodiment, thesandwiching member 400). The third region (in this embodiment, the highrigidity portion 423) which differs from the first region and the secondregion has higher rigidity than the first region and the second regionand hence, the deformation of the third region is suppressed by therigidity of the sandwiching member 400 per se without relying on othermembers. As described above, since all of the deformation of the firstregion, the second region and the third region are suppressed, thedeformation of the end plate can be suppressed.

According to this embodiment, the third region is formed of theplurality of plate members (in this embodiment, two plate members 425,426) which are made to overlap with each other and hence, the rigidityof the third region can be increased with the simple configuration.

According to this embodiment, the strip-like projecting portions 423 aare formed on the third region and hence, the rigidity of the thirdregion can be increased while the increase of a material and a weight ofthe sandwiching member 400 are suppressed.

According to this embodiment, the projecting portions 423 a are formedin an extending manner from the first region to the second region andhence, the rigidity of the third region can be further increased.

According to this embodiment, the second region is disposed at aposition corresponding to the recessed portions (in this embodiment, themounting portions 12 a) of the outer covering 10 and hence, the secondregion is positioned more inside the outer covering 10 compared to acase where the outer covering 10 has no such recessed portions.Accordingly, in the case where the third region is positioned betweenthe first region and the second region, a size of the third region canbe made small. As a result, the deformation which occurs on the thirdregion when a stress is applied to the third region can be furthersuppressed.

In this embodiment, the outer covering 10 is formed of a box-shapedcontainer. However, a shape of the outer covering 10 is not limited tosuch a shape. For example, the outer covering may have a cylindricalshape where a wall which forms a part of a plurality of walls forforming the box-shaped container is cut away. For example, the outercovering may be formed of: a pair of walls which face each other withthe energy storage devices 100 interposed therebetween; and columnarmembers or beam members which extend between and over the pair of walls.

For example, the outer covering may be formed of a plate-like base plateon which the plurality of energy storage devices 100 are placed andfixed. That is, the energy storage apparatus is not limited to theconfiguration where the energy storage devices 100 are fixed to theouter covering by fixing the end plates to the outer covering, and maybe configured such that the energy storage devices 100 per se are fixedto the outer covering. That is, the end plate may not have the secondregion to be fixed to the outer covering.

In this embodiment, although the outer covering 10 is provided as a bodyseparate from the binding members 500, the outer covering may beintegrally formed with the binding members. That is, some walls out of aplurality of walls which form the outer covering may function as thesandwiching members 400 in the above-mentioned embodiment, and otherwalls out of the plurality of walls may function as the binding members500 in the above-mentioned embodiment. Hereinafter, as a modification ofthe embodiment of the present invention, an energy storage apparatushaving such configurations is described.

(Modification)

FIG. 9 is an exploded perspective view showing respective constitutionalelements when an energy storage apparatus 1A according to a modificationof the embodiment of the present invention is disassembled. In thedrawing, hatching is applied to a high rigidity portion 123, and anouter covering 10A and energy storage devices 100 are described and theillustration of other constitutional elements is omitted.

The outer covering 10A shown in FIG. 9 includes: a first outer covering11A which forms a lid body of the outer covering 10A; and a second outercovering 12A which forms a body of the outer covering 10A. To be morespecific, the first outer covering 11A has an upper wall 111 f of theouter covering 10A, and the second outer covering 12A has side walls 111a to 111 d of the outer covering 10A, and a bottom wall 111 e of theouter covering 10A.

In the energy storage apparatus 1A having such a configuration, the sidewalls 111 a, 111 c function as end plates disposed on the sides of aunit of the energy storage devices 100, and the side walls 111 b, 111 dfunction as binding members which apply a binding force to the energystorage devices 100.

Hereinafter, the configurations of the side walls 111 a, 111 c aredescribed in detail. The side wall 111 a and the side wall 111 c havethe same configuration and hence, hereinafter, the configuration of theside wall 111 c is described and the description on the configuration ofthe side wall 111 a is omitted.

The side wall 111 c (end plate) has binding portions 121 and the highrigidity portion 123. The binding portions 121 are portions on which theside walls 111 b, 111 d (binding members) are mounted, and are disposedin a first region. The high rigidity portion 123 is a portion differentfrom the binding portions 121, has higher rigidity than the bindingportions 121, and is disposed in a third region. The high rigidityportion 123 is, for example, formed of a plurality of plate memberswhich are made to overlap with each other.

The energy storage apparatus 1A according to this modification havingthe above-mentioned configuration can also acquire substantially thesame advantageous effects as the energy storage apparatus 1 according tothe above-mentioned embodiment. That is, the deformation of the endplates (in this modification, the side walls 111 a, 111 c) can besuppressed. To be more specific, since the first regions (in thismodification, the binding portions 121) are mounted on the bindingmembers (in this modification, the side walls 111 b, 111 d), thedeformation of the first regions is suppressed by the binding members.Further, since the third region (in this modification, the high rigidityportion 123) which differs from the first regions has higher rigiditythan the first regions, the deformation of the third region issuppressed by the rigidity of the end plate per se without relying onother members. In this manner, since both the deformation of the firstregions and the third region are suppressed, in the same manner as theabove-mentioned embodiment, the deformation of the end plates can besuppressed.

Particularly, in this modification, the third region is disposed betweentwo first regions. Accordingly, the deformation of the third region canbe further suppressed.

(Other Modifications)

Although the energy storage apparatuses according to the embodiment ofthe present invention and the modifications of the embodiment have beendescribed heretofore, the present invention is not limited to theabove-mentioned embodiment and the modifications of the embodiment. Thatis, it should be construed that the embodiment and the modifications ofthe embodiment disclosed in this specification are only for anexemplifying purpose in all aspects and are not limited. The scope ofthe present invention is not designated by the above-mentioneddescription but is designated by Claims, and it is intended that allmodifications which fall within the meaning and the scope equivalent toClaims are also included in the scope of the present invention. Further,the configurations which are made by arbitrarily combining therespective constitutional elements which the above-mentioned embodimentand the modifications of the embodiment include are also included in thescope of the present invention.

For example, in the above-mentioned embodiment, the energy storageapparatus includes the pair of sandwiching members 400. However, thenumber of sandwiching members 400 is not particularly limited, and maybe one or three or more, for example. When the number of sandwichingmember is one, the sandwiching member 400 may sandwich the energystorage devices 100 together with the inner wall of the outer covering10 which faces the sandwiching member 400 with the energy storagedevices 100 interposed therebetween.

In the above-mentioned embodiment, the third region (in the descriptionmade heretofore, the high rigidity portion 423) is formed of two platemembers (in the description made heretofore, two plate members 425, 426)which are made to overlap with each other. However, the number of platemembers may be three or more. For example, the third region may beformed of the same plate member as the first region, and may be formedwith a wall thickness larger than that of the first region. That is, themetal end plate 420 may not be always formed of a plurality of platemembers which are made to overlap with each other, and may be formed ofone plate member.

In the above-mentioned embodiment, the strip-like projecting portions423 a are formed in the third region. However, the third region may nothave the projecting portions 423 a, but have a flat plate shape. It ispreferable that the projecting portion 423 a be formed into a stripshape from a viewpoint of effectively enhancing rigidity of the thirdregion. However, the projecting portion 423 a may be formed in a shapewhere the projecting portion 423 a becomes shorter than the case wherethe projecting portion 423 a is formed in a strip shape and theprojecting portion 423 a is formed locally.

In the above-mentioned embodiment, the outer covering 10 includes themounting portions 12 a each of which is formed of the recessed portionwhich is recessed toward the end plate. However, the mounting portions12 a may be formed without indentation. For example, the mountingportions 12 a may be formed coplanar with an outer surface of the bottomwall of the second outer covering 12. Further, in the above-mentionedembodiment, although the recessed portions are formed on the bottom wallof the second outer covering 12, the position where the recessedportions are formed is not limited to such a position. For example, therecessed portions may be formed on the side wall of the second outercovering 12 or may be formed on the first outer covering 11.

In the above-mentioned embodiment, the end plate is formed such that theplate-like member (the resin end plate 410) made of a resin and theplate-like member (the metal end plate 420) made of metal are made tooverlap with each other. However, the end plate is not limited to such aconfiguration. The end plate may be formed of one plate-like member madeof a resin or metal, or may be formed of a plate-like member made ofother material. Further, the end plate may be formed by arbitrarilycombining these plate-like members.

The present invention is applicable to an energy storage apparatus orthe like provided with energy storage devices and an outer covering.

What is claimed is:
 1. An energy storage apparatus comprising: an energystorage device; an outer covering; an end plate which is disposed on aside of the energy storage device and is fixed to the outer covering;and a binding member which is mounted on the end plate and applies abinding force to the energy storage device, wherein the end plateincludes a first region on which the binding member is mounted, a secondregion which is fixed to the outer covering, and a third region whichdiffers from the first region and the second region and has higherrigidity than the first region and the second region.
 2. The energystorage apparatus according to claim 1, wherein the end plate includes afirst plate member and a second plate member which are made to overlapwith each other in a first direction, and the first plate memberprojects from the second plate member in a second direction orthogonalto the first direction when the second plate member is viewed from thefirst direction, the first region is disposed at a position where thefirst plate member projects from the second plate member, and the thirdregion is disposed at a position where the first plate member and thesecond plate member are made to overlap with each other.
 3. The energystorage apparatus according to claim 2, wherein the second plate memberhas an overlapping portion which forms the third region by being made tooverlap with the first plate member, and a flange portion which projectsfrom the overlapping portion in the first direction and forms the secondregion.
 4. The energy storage apparatus according to claim 3, whereinthe second plate member has a strip-like projecting portion whichprojects in the first direction on the third region.
 5. The energystorage apparatus according to claim 4, wherein the third region ispositioned between the first region and the second region in the seconddirection when the end plate is viewed from the first direction, and theprojecting portion extends in the second direction in a strip shape onthe third region.
 6. The energy storage apparatus according to claim 4,wherein the number of fixing portions formed on the flange portion andthe number of projecting portions are equal.
 7. The energy storageapparatus according to claim 3, wherein the first plate member projectsaway from the energy storage device in the first region when the endplate is viewed in cross section, and the first plate member projects soas to approach to the energy storage device in the third region.
 8. Theenergy storage apparatus according to claim 1, wherein the outercovering has a recessed portion recessed toward the end plate, and thesecond region is disposed at a position corresponding to the recessedportion and is fixed to the recessed portion.
 9. The energy storageapparatus according to claim 1, further comprising an insulating platewhich is disposed between the energy storage device and the end plate,and the end plate is made of metal.
 10. An energy storage apparatuscomprising: an energy storage device; an outer covering; an end platewhich is disposed on a side of the energy storage device; and a bindingmember which is mounted on the end plate and applies a binding force tothe energy storage device, wherein the end plate includes a first regionwhere the binding member is mounted, and a third region which differsfrom the first region and has higher rigidity than the first region.